But all that will happen is that NBC will get less money. The local station will fill up more time with inane "our news is the greatest" stuff. The actual shows will still be just as long as they were, leaving 20 minutes or more per hour for commercials.
FWIW, even PBS is there - they run "enhanced" announcements for at least 15 minutes at the end of every show that are indistinguishable from commercials. Then they preempt everything for pledge drives every other month. We've gotten to the point where the TV is for watching movies (disc or streaming), watching selected streaming shows, or playing video games, except for occasional news or specific (pre-verified to actually be running) PBS stuff.